/*
 * Copyright 2002-2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.aop.support;

import java.io.Serializable;
import java.lang.reflect.Method;

import org.springframework.aop.MethodMatcher;
import org.springframework.aop.Pointcut;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * Pointcut constants for matching getters and setters,
 * and static methods useful for manipulating and evaluating pointcuts.
 * These methods are particularly useful for composing pointcuts
 * using the union and intersection methods.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 */
public abstract class Pointcuts {

    /**
     * Pointcut matching all bean property setters, in any class
     */
    public static final Pointcut SETTERS = SetterPointcut.INSTANCE;

    /**
     * Pointcut matching all bean property getters, in any class
     */
    public static final Pointcut GETTERS = GetterPointcut.INSTANCE;


    /**
     * Match all methods that <b>either</b> (or both) of the given pointcuts matches.
     *
     * @param pc1 the first Pointcut
     * @param pc2 the second Pointcut
     * @return a distinct Pointcut that matches all methods that either
     * of the given Pointcuts matches
     */
    public static Pointcut union(Pointcut pc1, Pointcut pc2) {
        return new ComposablePointcut(pc1).union(pc2);
    }

    /**
     * Match all methods that <b>both</b> the given pointcuts match.
     *
     * @param pc1 the first Pointcut
     * @param pc2 the second Pointcut
     * @return a distinct Pointcut that matches all methods that both
     * of the given Pointcuts match
     */
    public static Pointcut intersection(Pointcut pc1, Pointcut pc2) {
        return new ComposablePointcut(pc1).intersection(pc2);
    }

    /**
     * Perform the least expensive check for a pointcut match.
     *
     * @param pointcut    the pointcut to match
     * @param method      the candidate method
     * @param targetClass the target class
     * @param args        arguments to the method
     * @return whether there's a runtime match
     */
    public static boolean matches(Pointcut pointcut, Method method, Class<?> targetClass, Object... args) {
        Assert.notNull(pointcut, "Pointcut must not be null");
        if (pointcut == Pointcut.TRUE) {
            return true;
        }
        if (pointcut.getClassFilter().matches(targetClass)) {
            // Only check if it gets past first hurdle.
            MethodMatcher mm = pointcut.getMethodMatcher();
            if (mm.matches(method, targetClass)) {
                // We may need additional runtime (argument) check.
                return (!mm.isRuntime() || mm.matches(method, targetClass, args));
            }
        }
        return false;
    }


    /**
     * Pointcut implementation that matches bean property setters.
     */
    @SuppressWarnings("serial")
    private static class SetterPointcut extends StaticMethodMatcherPointcut implements Serializable {

        public static final SetterPointcut INSTANCE = new SetterPointcut();

        @Override
        public boolean matches(Method method, @Nullable Class<?> targetClass) {
            return (method.getName().startsWith("set") &&
                    method.getParameterCount() == 1 &&
                    method.getReturnType() == Void.TYPE);
        }

        private Object readResolve() {
            return INSTANCE;
        }
    }


    /**
     * Pointcut implementation that matches bean property getters.
     */
    @SuppressWarnings("serial")
    private static class GetterPointcut extends StaticMethodMatcherPointcut implements Serializable {

        public static final GetterPointcut INSTANCE = new GetterPointcut();

        @Override
        public boolean matches(Method method, @Nullable Class<?> targetClass) {
            return (method.getName().startsWith("get") &&
                    method.getParameterCount() == 0);
        }

        private Object readResolve() {
            return INSTANCE;
        }
    }

}
